Seattle King County Department of Public Health investigated an outbreak of salmonellosis (caused by Salmonella bacteria) associated with IHOP in Bellevue. The people who became sick reported eating a wide variety of breakfast foods at IHOP. Public Health reopened the investigation on March 27, 2024, after another person tested positive with same strain of Salmonella. Additionally, we have received confirmation that IHOP in Bellevue received onions that was part of a national recall. We were able to positively detect the same strain of Salmonella at the facility that since closed and did a thorough cleaning before reopening.

11 people from 11 separate households reported becoming sick. The people who became sick ranged in age from 17 to 70 years old. All 11 people developed one or more symptoms consistent with salmonellosis, including nausea, vomiting, abdominal cramps, diarrhea, bloody stool, and fever. We did not identify any ill employees.

At the time of our initial posting, we disclosed three cases linked to this outbreak. Since we were able to detect Salmonella Thompson in the facility, and since the facility received onions linked to a larger outbreak, we are including cases that were not previously confirmed to be part of this outbreak.

Public Health conducted interviews with the people who became sick to identify potential common exposures and identified that six became sick after eating at IHOP in Bellevue. No specific food was identified. Environmental Health Investigators requested source information and food receipts from the restaurants on January 11, 2024. Investigators visited the restaurant on January 16, 2024. Investigators reviewed the restaurant’s food preparation processes and did not identify factors that may have contributed to the outbreak. The facility conducted a thorough deep cleaning and reinforced food safety training with staff. After receiving notice of the positive case in late March, Environmental Health Investigators visited the facility on April 02, 2024, to test for the Salmonella strain. After detecting Salmonella Thompson in the facility, the food service facility closed on April 10, 2024, to complete a thorough cleaning and disinfection. Environmental Health Investigators revisited the facility on April 11, 2024, and verified proper compliance with cleaning and disinfection. The food facility reopened on Friday, April 12th.

All 11 cases had testing that identified Salmonella infections via culture. Further testing found all 11 cases had the same strain of Salmonella based on genetic fingerprinting (whole genome sequencing or WGS) at the Washington State Public Health Laboratory.

As of December 4, 2023, a total of 80 people infected with the outbreak strain of Salmonella were reported from 23 states. Illnesses started on dates ranging from August 2, 2023, to November 11, 2023. Of the 72 people with information available, 18 (25%) were hospitalized. One death from Wisconsin was reported.

Public health investigators used the PulseNet system to identify illnesses that may have been part of this outbreak. CDC PulseNet manages a national database of DNA fingerprints of bacteria that cause foodborne illnesses. DNA fingerprinting is performed on bacteria using a method called whole genome sequencing (WGS). WGS showed that bacteria from sick people’s samples were closely related genetically. This suggested that people in this outbreak got sick from the same food.

The outbreak strain was identified by FDA in October 2023 in environmental samples collected from the farm where the onions were grown. Other Salmonella strains were also identified from samples taken from the onion farm. CDC identified people who got sick with these strains of Salmonella, but there was not enough epidemiologic or traceback evidence to confirm these illnesses were part of the outbreak.

FDA conducted a traceback investigation and determined that onions processed at Gills Onions were available at points of service where people ate prior to becoming ill. Meal records from the long-term care facilities showed that people were served diced onions from Gills Onions.